The Tor Browser: netwerk/dns/race.c@b8a032363ba2 (annotated)

netwerk/dns/race.c@b8a032363ba2 (annotated)

netwerk/dns/race.c

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /*
  * Copyright (c) 2000,2001,2002 Japan Network Information Center.
  * All rights reserved.
  *
  * By using this file, you agree to the terms and conditions set forth bellow.
  *
  * 			LICENSE TERMS AND CONDITIONS
  *
  * The following License Terms and Conditions apply, unless a different
  * license is obtained from Japan Network Information Center ("JPNIC"),
  * a Japanese association, Kokusai-Kougyou-Kanda Bldg 6F, 2-3-4 Uchi-Kanda,
  * Chiyoda-ku, Tokyo 101-0047, Japan.
  *
  * 1. Use, Modification and Redistribution (including distribution of any
  *    modified or derived work) in source and/or binary forms is permitted
  *    under this License Terms and Conditions.
  *
  * 2. Redistribution of source code must retain the copyright notices as they
  *    appear in each source code file, this License Terms and Conditions.
  *
  * 3. Redistribution in binary form must reproduce the Copyright Notice,
  *    this License Terms and Conditions, in the documentation and/or other
  *    materials provided with the distribution.  For the purposes of binary
  *    distribution the "Copyright Notice" refers to the following language:
  *    "Copyright (c) 2000-2002 Japan Network Information Center.  All rights reserved."
  *
  * 4. The name of JPNIC may not be used to endorse or promote products
  *    derived from this Software without specific prior written approval of
  *    JPNIC.
  *
  * 5. Disclaimer/Limitation of Liability: THIS SOFTWARE IS PROVIDED BY JPNIC
  *    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  *    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  *    PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL JPNIC BE LIABLE
  *    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  *    CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  *    SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  *    BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  *    WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  *    OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  *    ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
  */
 #include <stddef.h>
 #include <stdlib.h>
 #include <string.h>
 #include "nsIDNKitInterface.h"
 #define RACE_2OCTET_MODE	0xd8
 #define RACE_ESCAPE		0xff
 #define RACE_ESCAPE_2ND		0x99
 /*
  * Compression type.
  */
 enum {
 	compress_one,	/* all characters are in a single row */
 	compress_two,	/* row 0 and another row */
 	compress_none	/* nope */
 };
 idn_result_t
 race_decode_decompress(const char *from, uint16_t *buf, size_t buflen)
 {
 	uint16_t *p = buf;
 	unsigned int bitbuf = 0;
 	int bitlen = 0;
 	unsigned int i, j;
 	size_t len;
 	while (*from != '\0') {
 		int c = *from++;
 		int x;
 		if ('a' <= c && c <= 'z')
 			x = c - 'a';
 		else if ('A' <= c && c <= 'Z')
 			x = c - 'A';
 		else if ('2' <= c && c <= '7')
 			x = c - '2' + 26;
 		else
 			return (idn_invalid_encoding);
 		bitbuf = (bitbuf << 5) + x;
 		bitlen += 5;
 		if (bitlen >= 8) {
 			*p++ = (bitbuf >> (bitlen - 8)) & 0xff;
 			bitlen -= 8;
 		}
 	}
 	len = p - buf;
 	/*
 	 * Now 'buf' holds the decoded string.
 	 */
 	/*
 	 * Decompress.
 	 */
 	if (buf[0] == RACE_2OCTET_MODE) {
 		if ((len - 1) % 2 != 0)
 			return (idn_invalid_encoding);
 		for (i = 1, j = 0; i < len; i += 2, j++)
 			buf[j] = (buf[i] << 8) + buf[i + 1];
 		len = j;
 	} else {
 		uint16_t c = buf[0] << 8;	/* higher octet */
 		for (i = 1, j = 0; i < len; j++) {
 			if (buf[i] == RACE_ESCAPE) {
 				if (i + 1 >= len)
 					return (idn_invalid_encoding);
 				else if (buf[i + 1] == RACE_ESCAPE_2ND)
 					buf[j] = c | 0xff;
 				else
 					buf[j] = buf[i + 1];
 				i += 2;
 			} else if (buf[i] == 0x99 && c == 0x00) {
 				/*
 				 * The RACE specification says this is error.
 				 */
 				return (idn_invalid_encoding);
 			} else {
 				buf[j] = c | buf[i++];
 			}
 		}
 		len = j;
 	}
 	buf[len] = '\0';
 	return (idn_success);
 }
 idn_result_t
 race_compress_encode(const uint16_t *p, int compress_mode,
 		     char *to, size_t tolen)
 {
 	uint32_t bitbuf = *p++;	/* bit stream buffer */
 	int bitlen = 8;			/* # of bits in 'bitbuf' */
 	while (*p != '\0' || bitlen > 0) {
 		unsigned int c = *p;
 		if (c == '\0') {
 			/* End of data.  Flush. */
 			bitbuf <<= (5 - bitlen);
 			bitlen = 5;
 		} else if (compress_mode == compress_none) {
 			/* Push 16 bit data. */
 			bitbuf = (bitbuf << 16) | c;
 			bitlen += 16;
 			p++;
 		} else {/* compress_mode == compress_one/compress_two */
 			/* Push 8 or 16 bit data. */
 			if (compress_mode == compress_two &&
 			    (c & 0xff00) == 0) {
 				/* Upper octet is zero (and not U1). */
 				bitbuf = (bitbuf << 16) | 0xff00 | c;
 				bitlen += 16;
 			} else if ((c & 0xff) == 0xff) {
 				/* Lower octet is 0xff. */
 				bitbuf = (bitbuf << 16) |
 					(RACE_ESCAPE << 8) | RACE_ESCAPE_2ND;
 				bitlen += 16;
 			} else {
 				/* Just output lower octet. */
 				bitbuf = (bitbuf << 8) | (c & 0xff);
 				bitlen += 8;
 			}
 			p++;
 		}
 		/*
 		 * Output bits in 'bitbuf' in 5-bit unit.
 		 */
 		while (bitlen >= 5) {
 			int x;
 			/* Get top 5 bits. */
 			x = (bitbuf >> (bitlen - 5)) & 0x1f;
 			bitlen -= 5;
 			/* Encode. */
 			if (x < 26)
 				x += 'a';
 			else
 				x = (x - 26) + '2';
 			if (tolen < 1)
 				return (idn_buffer_overflow);
 			*to++ = x;
 			tolen--;
 		}
 	}
 	if (tolen <= 0)
 		return (idn_buffer_overflow);
 	*to = '\0';
 	return (idn_success);
 }
 int
 get_compress_mode(uint16_t *p) {
 	int zero = 0;
 	unsigned int upper = 0;
 	uint16_t *modepos = p - 1;
 	while (*p != '\0') {
 		unsigned int hi = *p++ & 0xff00;
 		if (hi == 0) {
 			zero++;
 		} else if (hi == upper) {
 			;
 		} else if (upper == 0) {
 			upper = hi;
 		} else {
 			*modepos = RACE_2OCTET_MODE;
 			return (compress_none);
 		}
 	}
 	*modepos = upper >> 8;
 	if (upper > 0 && zero > 0)
 		return (compress_two);
 	else
 		return (compress_one);
 }

The Tor Browser / annotate

netwerk/dns/race.c@b8a032363ba2 (annotated)

netwerk/dns/race.c